Electrohydraulic normally-open ventable valve configured to operate in pressure relief mode when actuated

ABSTRACT

An example valve includes: (i) a pilot seat member comprising: (a) one or more channels fluidly coupled to a first port of the valve, (b) a pilot seat, and (c) a pilot sleeve portion comprising a pilot chamber and a cross-hole disposed in an exterior peripheral surface of the pilot sleeve portion; (ii) a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring disposed in the pilot chamber to seat the pilot check member at the pilot seat; and (iii) a solenoid actuator sleeve slidably accommodated about the exterior peripheral surface of the pilot sleeve portion of the pilot seat member, wherein the solenoid actuator sleeve includes a cross-hole disposed in an exterior peripheral surface of the solenoid actuator sleeve, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to a second port of the valve.

BACKGROUND

A relief valve or pressure relief valve (PRV) is a type of safety valveused to control or limit the pressure in a system. Pressure mightotherwise build up and can cause equipment failure. The pressure isrelieved by allowing the pressurized fluid to flow out of the system toa tank or low pressure fluid reservoir. In some applications, a PRV canbe used to build pressure level of fluid up to a particular pressurelevel to operate a hydraulic system or component.

A PRV is designed or set to open at a predetermined setting pressure toprotect other components and other equipment from being subjected topressures that exceed their design limits. When the setting pressure isexceeded, the PRV becomes or forms the “path of least resistance” as thePRV is forced open and a portion of fluid is diverted to the tank. Asthe fluid is diverted, the pressure inside the system stops rising. Oncethe pressure is reduced and reaches the PRV's reseating pressure, thePRV closes.

SUMMARY

The present disclosure describes implementations that relate to anelectrohydraulic normally-open ventable valve configured to operate inpressure relief mode when actuated.

In a first example implementation, the present disclosure describes avalve. The valve includes: (i) a pilot seat member comprising: (a) oneor more channels fluidly coupled to a first port of the valve, (b) apilot seat, and (c) a pilot sleeve portion comprising a pilot chamberand a cross-hole disposed in an exterior peripheral surface of the pilotsleeve portion; (ii) a pilot check member disposed in the pilot chamberand subjected to a biasing force of a setting spring disposed in thepilot chamber to seat the pilot check member at the pilot seat; and(iii) a solenoid actuator sleeve slidably accommodated about theexterior peripheral surface of the pilot sleeve portion of the pilotseat member, wherein the solenoid actuator sleeve includes a cross-holedisposed in an exterior peripheral surface of the solenoid actuatorsleeve, wherein the cross-hole of the solenoid actuator sleeve isfluidly coupled to a second port of the valve. When the valve isunactuated, the cross-hole of the solenoid actuator sleeve is fluidlycoupled to the one or more channels of the pilot seat member to form afirst pilot flow path from the first port to the second port, therebycausing a piston to move and open a main flow path from the first portto the second port. When the valve is actuated, the solenoid actuatorsleeve moves axially, thereby: (i) blocking the first pilot flow path,(ii) causing the piston to block the main flow path from the first portto the second port, and (iii) aligning the cross-hole of the solenoidactuator sleeve with the cross-hole of the pilot sleeve portion, suchthat when pressure level of fluid at the first port overcomes thebiasing force of the setting spring on the pilot check member, the pilotcheck member is unseated and a second pilot flow path is formed from thefirst port to the second port, thereby causing the piston to moveaxially and open the main flow path from the first port to the secondport.

In a second example implementation, the present disclosure describes ahydraulic system including a source of fluid; a reservoir; and aventable pressure relief valve having a first port fluidly coupled tothe source of fluid, and a second port fluidly coupled to the reservoir.The ventable pressure relief valve comprises: (i) a pilot seat membercomprising: (a) one or more channels fluidly coupled to the first port,(b) a pilot seat, and (c) a pilot sleeve portion comprising a pilotchamber and a cross-hole disposed in an exterior peripheral surface ofthe pilot sleeve portion; (ii) a pilot check member disposed in thepilot chamber and subjected to a biasing force of a setting springdisposed in the pilot chamber to seat the pilot check member at thepilot seat; and (iii) a solenoid actuator sleeve slidably accommodatedabout the exterior peripheral surface of the pilot sleeve portion of thepilot seat member, wherein the solenoid actuator sleeve includes across-hole disposed in an exterior peripheral surface of the solenoidactuator sleeve, wherein the cross-hole of the solenoid actuator sleeveis fluidly coupled to the second port. When the ventable pressure reliefvalve is unactuated, the ventable pressure relief valve operates in aventable mode of operation, wherein the cross-hole of the solenoidactuator sleeve is fluidly coupled to the one or more channels of thepilot seat member to form a first pilot flow path from the first port tothe second port, thereby causing a piston to move and open a main flowpath from the first port to the second port. When the ventable pressurerelief valve is actuated, the ventable pressure relief valve operates ina pressure relief mode of operation, wherein the solenoid actuatorsleeve moves axially, thereby: (i) blocking the first pilot flow path,(ii) causing the piston to block the main flow path from the first portto the second port, and (iii) aligning the cross-hole of the solenoidactuator sleeve with the cross-hole of the pilot sleeve portion, suchthat when pressure level of fluid at the first port overcomes thebiasing force of the setting spring on the pilot check member, the pilotcheck member is unseated and a second pilot flow path is formed from thefirst port to the second port, thereby causing the piston to moveaxially and open the main flow path from the first port to the secondport.

In a third example implementation, the present disclosure describes avalve. The valve includes: (i) a housing having a longitudinalcylindrical cavity therein and having a cross-hole disposed in anexterior peripheral surface of the housing; (ii) a main sleeve disposed,at least partially, in the longitudinal cylindrical cavity of thehousing, wherein the main sleeve includes a first port at a distal endof the main sleeve and includes one or more cross-holes disposed on anexterior peripheral surface of the main sleeve, wherein the cross-holeof the housing and the one or more cross-holes of the main sleeve form asecond port; (iii) a piston disposed within the main sleeve andconfigured to be axially movable therein, wherein the piston defines amain chamber therein, and wherein the main chamber is fluidly coupled tothe first port via an orifice; (iv) a pilot seat member comprising: (a)one or more channels fluidly coupled to the main chamber, (b) a pilotseat, and (c) a pilot sleeve portion comprising a pilot chamber and across-hole disposed in an exterior peripheral surface of the pilotsleeve portion; (v) a pilot check member disposed in the pilot chamberand subjected to a biasing force of a setting spring disposed in thepilot chamber to seat the pilot check member at the pilot seat; and (vi)a solenoid actuator sleeve slidably accommodated about the exteriorperipheral surface of the pilot sleeve portion of the pilot seat member,wherein the solenoid actuator sleeve includes a cross-hole disposed inan exterior peripheral surface of the solenoid actuator sleeve, whereinthe cross-hole of the solenoid actuator sleeve is fluidly coupled to thesecond port. When the valve is unactuated, the solenoid actuator sleeveis in a first position in which the cross-hole of the solenoid actuatorsleeve is fluidly coupled to the one or more channels of the pilot seatmember to form a first pilot flow path from the first port to the secondport. When the valve is actuated, the solenoid actuator sleeve movesaxially to a second position in which the first pilot flow path isblocked, and the cross-hole of the solenoid actuator sleeve is alignedwith the cross-hole of the pilot sleeve portion to form a second pilotflow path when pressure level of fluid at the first port overcomes thebiasing force of the setting spring on the pilot check member.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects,implementations, and features described above, further aspects,implementations, and features will become apparent by reference to thefigures and the following detailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a cross-sectional side view of a valve in a ventableoperation mode, in accordance with an example implementation.

FIG. 2 illustrates a three-dimensional perspective view showing anarmature coupled to a solenoid actuator sleeve, in accordance with anexample implementation.

FIG. 3 illustrates a cross-sectional side view of a valve in a pressurerelief mode of operation, in accordance with another exampleimplementation.

FIG. 4 illustrates a cross-section side view of a valve having a manualadjustment actuator, in accordance with an example implementation.

FIG. 5 illustrates a cross-sectional side view of a solenoid tube, inaccordance with an example implementation.

FIG. 6 illustrates a hydraulic circuit using the valve shown in FIG. 4,in accordance with an example implementation.

FIG. 7 is a flowchart of a method for controlling a hydraulic system, inaccordance with an example implementation.

FIG. 8 is a flowchart of a method for operating a valve, in accordancewith an example implementation.

DETAILED DESCRIPTION

Pressure relief valves are configured to open at a preset pressure anddischarge fluid until pressure drops to acceptable levels in a system.In operation, the pressure relief valve can remain normally-closed untilpressure upstream reaches a desired setting pressure. The valve can then“crack” open when the setting pressure is reached, and continue to openfurther, allowing more flow as pressure increases. When upstreampressure falls below the setting pressure, the valve can close again.

In some examples, it may be desirable to have a ventable pressure reliefvalve that can provide system relief protection with an actuation signal(e.g., with an electrical signal) combined with the ability to “unload”a source of fluid (e.g., a pump) to a tank when unactuated. For example,the valve can operate in a ventable operation mode to unload a pump aslong as a speed of an engine or motor driving the pump is below aparticular threshold speed. Once the particular threshold speed, thevalve can be actuated to switch to a pressure relief mode. In anotherexample, the valve can operate in the ventable operation mode when thetemperature of hydraulic oil exceeds a particular temperature threshold,and then actuated to operate in the pressure relief mode when thetemperature is reduced to a value below the particular temperaturethreshold. In other examples, the valve can operate in the ventableoperation mode to operate the hydraulic system in a safety mode, andthen actuated to switch the valve to the pressure relief mode when thehydraulic system is ready to be operational.

It may also be desirable to have such combined functionality in acompact package that does not involve using several valves, but rather asingle valve that combines multiple functionalities, thereby reducingmanufacturing cost. Further, having a compact package that performsmultiple functionalities reduces system size and weight.

Disclosed herein is a valve configured to operate in a ventable mode tomaintain low system pressure until the valve is actuated. Particularly,when the valve is unactuated, the valve forms therein a first pilot flowpath that is open, thereby causing the valve to operate in the ventablemode. Upon actuation, the valve is configured to block the first pilotflow path and operate as a relief valve that forms a second pilot flowpath configured to allow fluid flow therethrough when a relief setting(i.e., the setting pressure) is reached.

FIG. 1 illustrates a cross-sectional side view of a valve 100 in aventable operation mode, in accordance with an example implementation.The valve 100 may be inserted or screwed into a manifold having portscorresponding to ports of the valve 100 described below, and can thusfluidly coupled the valve 100 to other components of a hydraulic system.

The valve 100 may include a main stage 102, a pilot stage 104, and asolenoid actuator 106. The valve 100 includes a housing 108 thatincludes a longitudinal cylindrical cavity therein. The longitudinalcylindrical cavity of the housing 108 is configured to house portions ofthe main stage 102, the pilot stage 104, and the solenoid actuator 106.

The main stage 102 includes a main sleeve 110 received at a distal endof the housing 108, and the main sleeve 110 is coaxial with the housing108. The valve 100 includes a first port 112 and a second port 114. Thefirst port 112 is defined at a nose or distal end of the main sleeve110. The second port 114 can include a first set of cross-holes that canbe referred to as main flow cross-holes, such as main flow cross-holes115A, 115B, disposed in a radial array about an exterior surface of themain sleeve 110. The second port 114 can also include a second set ofcross-holes that can be referred to as pilot flow cross-holes, such aspilot flow cross-hole 116 disposed in the housing 108.

The main sleeve 110 includes a respective longitudinal cylindricalcavity therein. The valve 100 includes a piston 118 that is disposed,and slidably accommodated, in the longitudinal cylindrical cavity of themain sleeve 110. The term “piston” is used herein to encompass any typeof movable element, such as a spool-type movable element or apoppet-type movable element. The piston 118 is shown in the figures as aspool-type movable element; however, it is contemplated that apoppet-type movable element can be used instead. In the case apoppet-type movable element is used, the inner peripheral surface of themain sleeve 110 can form a protrusion that operates as a seat for thepoppet-type movable element and reduce leakage through the valve 100.

Further, the term “slidably accommodated” is used throughout herein toindicate that a first component (e.g., the piston 118) is positionedrelative to a second component (e.g., the main sleeve 110) withsufficient clearance therebetween, enabling movement of the firstcomponent relative to the second component in the proximal and distaldirections. As such, the first component (e.g., piston 118) is notstationary, locked, or fixedly disposed in the valve 100, but rather, isallowed to move relative to the second component (e.g., the main sleeve110).

The piston 118 has a cavity or main chamber 120 therein, and the valve100 includes a main spring 122 disposed in the main chamber 120 of thepiston 118. The valve 100 also includes a ring-shaped member 124disposed, at least partially, within the piston 118 at a distal endthereof. The ring-shaped member 124 includes a filter 126 and formstherein an orifice 128 that fluidly couples the first port 112 to themain chamber 120.

The valve 100 further includes a pilot seat member 130 fixedly disposedat the proximal end of the main sleeve 110 within the cavity of thehousing 108. As shown in FIG. 1, the pilot seat member 130 has ashoulder formed by an exterior peripheral surface of the pilot seatmember 130. The shoulder interfaces with the proximal end of the mainsleeve 110 and interfaces with a shoulder 131 formed as a protrusionfrom an interior peripheral surface of the housing 108. As such, thepilot seat member 130 is fixedly disposed within the housing 108.

The main spring 122 is disposed in the main chamber 120 such that adistal end of the main spring 122 rests against the interior surface ofthe piston 118, and a proximal end of the main spring 122 rests againstthe pilot seat member 130. The pilot seat member 130 is fixed, and thusthe main spring 122 biases the piston 118 in the distal direction (tothe right in FIG. 1). The distal direction could also be referred to asa closing direction. The main spring 122 is configured as a weak spring(e.g., a spring with a spring rate of 8 pound-force/inch causing a 2pound-force biasing force on the piston 118). With such a low springrate, a low pressure level differential across the piston 118, e.g.,pressure level differential of 25 pounds per square inch (psi), cancause the piston 118 to move in the proximal direction against thebiasing force of the main spring 122.

Further, the pilot seat member 130 includes one or more channels thatare fluidly coupled to the first port 112. For example, the pilot seatmember 130 can include a longitudinal channel 132 and can also include aplurality of radial channels such as radial channel 134 fluidly coupledto the longitudinal channel 132. The longitudinal channel 132 canoperate as a damping orifice, such that as fluid flows from the firstport 112, through the orifice 128 and the main chamber 120, pressurelevel of the fluid can drop as it flows through the longitudinal channel132.

The pilot seat member 130 forms a pilot seat 136 at a proximal end ofthe longitudinal channel 132. The pilot stage 104 of the valve 100includes a pilot poppet 138 configured to be seated at the pilot seat136. In particular, with the configuration shown in FIG. 1, the pilotpoppet 138 forms a cavity at its distal end that is configured to housea pilot check ball 139. The pilot check ball 139 is configured to beseated at the pilot seat 136 when the valve 100 is in the ventable modeof operation depicted in FIG. 1.

The pilot poppet 138 and the pilot check ball 139 can be collectivelyreferred to as a pilot check member 140. The configuration of the pilotcheck member 140 that includes the pilot poppet 138 and the pilot checkball 139 as shown in FIG. 1 is an example for illustration. In otherexamples, a pilot check member can be configured as a poppet having anose section that tapers gradually, such that rather than using a checkball to block fluid flow, an exterior surface of the nose section of thepoppet is seated at the pilot seat 136 to block fluid flow.

As shown in FIG. 1, the pilot seat member 130 has a pilot sleeve portion141 that extends in the proximal direction within the housing 108 andforms therein a pilot chamber 142 in which the pilot poppet 138 isdisposed and is slidably accommodated therein. The pilot poppet 138 isthus guided by an interior peripheral surface of the pilot sleeveportion 141 when the pilot poppet 138 moves axially in a longitudinaldirection.

The pilot stage 104 further includes a setting spring 144 disposed inthe pilot chamber 142, such that a distal end of the setting spring 144interfaces with the pilot poppet 138 and biases the pilot poppet 138toward the pilot seat 136. As such, the pilot poppet 138 operates as adistal spring cap for the setting spring 144.

A proximal end of the setting spring 144 rests against a washer 146disposed in the pilot chamber 142 and fixed in place via a springpreload adjustment screw 148. The spring preload adjustment screw 148has a threaded region on its exterior peripheral surface that threadedlyengages with a corresponding threaded region on an interior peripheralsurface of the pilot sleeve portion 141 of the pilot seat member 130.

The valve 100 can further include a pin 149 that secures that springpreload adjustment screw 148 within the pilot sleeve portion 141. Forexample, the pin 149 can be disposed partially within a longitudinalgroove formed in the exterior peripheral surface of the spring preloadadjustment screw 148 and partially within a longitudinal groove formedin the interior peripheral surface of the pilot sleeve portion 141. Assuch, the pin 149 couples and secures the spring preload adjustmentscrew 148 to the pilot sleeve portion 141. In an example, the pin 149can be pushed into the longitudinal groove formed on the exteriorperipheral of the spring preload adjustment screw 148, and as the pin149 is forced in longitudinal groove, it deforms interior threads of thepilot sleeve portion 141. As such, once the spring preload adjustmentscrew 148 is screwed into the pilot seat member 130 to a particularlongitudinal or axial position, and the pin 149 is inserted, positionsof the spring preload adjustment screw 148 and the washer 146 are fixed,as the spring preload adjustment screw 148 can no longer rotate relativeto the pilot seat member 130.

The biasing force of the setting spring 144 determines the pressurerelief setting of the valve 100, where the pressure relief setting isthe pressure level of fluid at the first port 112 at which the valve 100can open to relieve fluid to the second port 114. Specifically, based ona spring rate of the setting spring 144 and the length of the settingspring 144, the setting spring 144 exerts a particular preload orbiasing force on the pilot poppet 138 in the distal direction, thuscausing the pilot check ball 139 to be seated at the pilot seat 136 ofthe pilot seat member 130. The pressure relief setting of the valve 100can be determined by dividing the biasing force that the setting spring144 applies to the pilot poppet 138 by an effective area of the pilotseat 136. The effective area of the pilot seat 136 can be estimated as acircular area having a diameter of the pilot seat 136. As an example forillustration, the pressure relief setting of the valve 100 can be about5000 psi.

As described below, when the valve 100 is actuated and when pressurelevel of fluid at the first port 112 causes the fluid to apply a forceon the pilot check ball 139, and thus on the pilot poppet 138, in theproximal direction that overcomes the biasing force of the settingspring 144 applied on the pilot poppet 138 in the distal direction, thepilot poppet 138 and the pilot check ball 139 move off the pilot seat136. As the pilot check ball 139 is unseated, a pilot flow is allowed,thereby causing main flow from the first port 112 to the second port 114and relieving the fluid as described below.

Adjusting longitudinal position of the spring preload adjustment screw148 within the pilot seat member 130 (prior to installation of the pin149) can adjust the biasing force of the setting spring 144. Forexample, if the spring preload adjustment screw 148 is rotated in afirst direction (e.g., in a clockwise direction), the spring preloadadjustment screw 148 may move axially in the distal direction (e.g., tothe right in FIG. 1) pushing the washer 146 in the distal direction,thus compressing the setting spring 144 and increasing the preload orbiasing force of the setting spring 144.

Conversely, rotating the spring preload adjustment screw 148 in a seconddirection (e.g., counter-clockwise) causes the spring preload adjustmentscrew 148 to move axially in the proximal direction, allowing thesetting spring 144 to push the washer 146 in the proximal direction. Thelength of the setting spring 144 thus increases and the preload orbiasing force of the setting spring 144 is reduced.

In examples, the spring preload adjustment screw 148 can be hollow suchthat a force sensor (e.g., a pin configured to have a force sensorcoupled thereto) can be inserted from the proximal end of the valve 100(prior to installation of the solenoid actuator 106) through the springpreload adjustment screw 148 to contact the washer 146 and measure thebiasing force of the setting spring 144. With this configuration, ifdesired, the biasing force of the setting spring 144, and thus thepressure relief setting of the valve 100, can be adjusted by adjustingthe longitudinal or axial position of the spring preload adjustmentscrew 148, prior to completing assembly of the valve 100 (i.e., prior toinstallation of the pin 149 and the solenoid actuator 106).

The solenoid actuator 106 includes a solenoid tube 150 configured as acylindrical housing or body disposed within and received at a proximalend of the housing 108, such that the solenoid tube 150 is coaxial withthe housing 108. For instance, the solenoid tube 150 can have a threadedregion disposed on an exterior peripheral surface at a distal endthereof that threadedly engages with a corresponding threaded regionformed on an interior peripheral surface of the housing 108 at aproximal end thereof. A solenoid coil 151 can be disposed about anexterior surface of the solenoid tube 150. The solenoid coil 151 isretained between a proximal end of the housing 108 and a coil nut 153having internal threads that can engage a threaded region formed on theexterior peripheral surface of the solenoid tube 150 at its proximalend.

The solenoid tube 150 forms therein a solenoid actuator chamberconfigured to house a plunger or armature 152. The armature 152 isslidably accommodated within the solenoid tube 150.

The solenoid actuator 106 further includes a solenoid actuator sleeve154 received at the proximal end of the housing 108 and also disposedpartially within a distal end of the solenoid tube 150. The solenoidactuator sleeve 154 is slidably accommodated about the exteriorperipheral surface of the pilot sleeve portion 141 (i.e., the solenoidactuator sleeve 154 is positioned relative to the pilot sleeve portion141 with sufficient clearance therebetween, enabling movement of thesolenoid actuator sleeve 154 relative to the pilot sleeve portion 141 inthe proximal and distal directions, and thus the solenoid actuatorsleeve 154 is not stationary, locked, or fixedly disposed in the valve100, but rather, is allowed to move relative to the pilot sleeve portion141).

Further, the solenoid actuator sleeve 154 includes a plurality ofcross-holes, such as cross-holes 155A, 155B, disposed in a radial arrayabout an exterior surface of the solenoid actuator sleeve 154 andconfigured to communicate fluid therethrough.

Further, the armature 152 is mechanically coupled to, or linked with,the solenoid actuator sleeve 154. As such, if the armature 152 movesaxially (e.g., in the proximal direction), the solenoid actuator sleeve154 moves along with the armature 152 in the same direction.

The armature 152 can be coupled to the solenoid actuator sleeve 154 inseveral ways. FIG. 2 illustrates a three-dimensional partial perspectiveview showing the armature 152 coupled to the solenoid actuator sleeve154, in accordance with an example implementation. As shown, thesolenoid actuator sleeve 154 can have a male T-shaped member 200, andthe armature 152 can have a corresponding female T-slot 202 configuredto receive the male T-shaped member 200 of the solenoid actuator sleeve154. With this configuration, the armature 152 and the solenoid actuatorsleeve 154 are coupled to each other, such that if the armature 152moves, the solenoid actuator sleeve 154 moves therewith.

Referring back to FIG. 1, the solenoid tube 150 further includes a polepiece 156 that can be separated from the armature 152 by an airgap 158.The pole piece 156 can be composed of material of high magneticpermeability.

The armature 152 includes therein a channel 160 and a chamber 162 formedwithin the armature 152 at a proximal end thereof. The chamber 162 isthus bounded by an interior surface of the pole piece 156 and aninterior surface of the armature 152. As such, fluid received at thefirst port 112 can be communicated through unsealed spaces within thevalve 100 to the channel 160, then to the chamber 162 and the airgap158. With this configuration, the armature 152 can be pressure-balancedwith fluid acting on both its proximal and distal ends.

Further, in examples, the chamber 162 can house a solenoid spring 164that biases the armature 152 toward the solenoid actuator sleeve 154 andthe pilot sleeve portion 141 such that there is no axial clearance oraxial “play” between the armature 152, the solenoid actuator sleeve 154,and the pilot sleeve portion 141, thus maintaining contact therebetween,when the valve 100 is unactuated. When the valve 100 is actuated, asdescribed below, the armature 152 can move in the proximal directionagainst the force of the solenoid spring 164, and thus the solenoidactuator sleeve 154 can move relative to (e.g., slide about the exteriorperipheral surface of) the pilot sleeve portion 141, which is fixed. Thesolenoid spring 164 can be a weak spring that applies a low force on thearmature 152. As an example for illustration, the solenoid spring 164can have a spring rate of 30 pound-force/inch causing a force of about2.5 pound-force on the armature 152.

The valve 100 is configured to operate in at least two modes ofoperation. The first mode of operation when the valve 100 is unactuatedcan be referred to as the ventable mode of operation and is depicted inFIG. 1. In this mode of operation, as shown in FIG. 1, the solenoidactuator sleeve 154 is in a first position, where the radial channel 134of the pilot seat member 130 is overlapped, at least partially, with thecross-holes 155A, 155B of the solenoid actuator sleeve 154. In otherwords, the cross-holes 155A, 155B of the solenoid actuator sleeve 154are aligned with, and fluidly coupled to, the radial channel 134 of thepilot seat member 130. Thus, fluid received at the first port 112 canflow through the orifice 128, the main chamber 120, the longitudinalchannel 132, and the radial channel 134 to the cross-holes 155A, 155B.

As shown in FIG. 1, an exterior diameter of the solenoid actuator sleeve154 is smaller than an interior diameter of the housing 108, and thusannular space 166 is formed therebetween. Also, the pilot seat member130 includes a plurality of longitudinal channels or through-holes suchas longitudinal through-hole 168 disposed in a radial array around thepilot seat member 130. Further, the longitudinal through-hole 168 isfluidly coupled to the pilot flow cross-hole 116 of the housing 108 viaan annular undercut or annular groove 170 formed on the exteriorperipheral surface of the main sleeve 110 at a proximal end thereof.

As such, in the ventable valve mode of operation, fluid received at thefirst port 112 flows to the second port 114 through the orifice 128, themain chamber 120, the longitudinal channel 132, the radial channel 134,the cross-holes 155A, 155B, the annular space 166, the longitudinalthrough-hole 168, the annular groove 170, and the pilot flow cross-hole116. Such fluid flow from the first port 112 to the second port 114through the pilot flow cross-hole 116 can be referred to as the pilotflow. As an example for illustration, the pilot flow can amount to about0.15 gallons per minute (GPM).

With this configuration, in the ventable mode of operation, when thevalve 100 is unactuated (i.e., when the solenoid coil 151 isun-energized), the valve 100 forms a first pilot flow path from thefirst port 112 through the orifice 128, the main chamber 120, thelongitudinal channel 132, the radial channel 134, the cross-holes 155A,155B, the annular space 166, the longitudinal through-hole 168, theannular groove 170, and the pilot flow cross-hole 116 to the second port114. The first pilot flow path is normally-open, i.e., when the valve100 is in an unactuated state, the first pilot flow path through theradial channel 134 is open.

The pilot flow through the orifice 128, which operates as a flowrestriction, causes a pressure drop in the pressure level of the fluid.Thus, the pressure level of fluid in the main chamber 120 becomes lowerthan the pressure level of fluid received at the first port 112. As aresult, fluid at the first port 112 applies a force on the distal end ofthe piston 118 in the proximal direction (e.g., to the left in FIG. 1)that is larger than the force applied by fluid in the main chamber 120on the proximal end of the piston 118 in the distal direction (e.g., tothe right in FIG. 1).

Due to such force imbalance on the piston 118, a net force is applied tothe piston 118 in the proximal direction. When the net force overcomesthe biasing force of the main spring 122 on the piston 118, the netforce causes the piston 118 to move or be displaced axially in theproximal direction against the biasing force of the main spring 122. Asmentioned above, the main spring 122 has a low spring rate, and thus asmall pressure drop (e.g., when the pressure drop across the orifice 128is about 25 psi) can cause the net force to overcome the biasing forceof the main spring 122 on the piston 118. The piston 118 can move in theproximal direction until the proximal end of the piston 118 interfaceswith or contacts the distal end of the pilot seat member 130, whichoperates as a stop for the piston 118.

In the position shown in FIG. 1, i.e., when the piston 118 has moved inthe proximal direction, the main flow cross-holes 115A, 115B areexposed, and thus fluid received at the first port 112 is allowed toflow through the main flow cross-holes 115A, 115B directly to the secondport 114. In other words, a main flow path is formed from the first port112 directly through the main flow cross-holes 115A, 115B to the secondport 114. Such direct flow from the first port 112 to the second port114 can be referred to as the main flow. As an example for illustration,the main flow rate can amount to up to 25 GPM based on the pressuresetting of the valve 100 and the pressure drop between the first port112 and the second port 114. The 25 GPM main flow rate is an example forillustration only. The valve 100 is scalable in size and differentamounts of main flow rates can be achieved.

The second port 114 can be coupled to a low pressure reservoir or tankhaving fluid at low pressure level (e.g., atmospheric or low pressurelevel such as 10-70 psi). As such, fluid at the first port 112 is ventedto the tank, and pressure level does not build up or increase at thefirst port 112.

As a result, the pressure level of fluid communicated through thelongitudinal channel 132 and acting on the pilot check ball 139 is notsufficient to overcome the biasing force of the setting spring 144.Therefore, the pilot poppet 138 and the pilot check ball 139 remainseated at the pilot seat 136, precluding fluid flow to within the pilotsleeve portion 141.

The pilot sleeve portion 141 includes cross-holes, such as cross-holes172A, 172B disposed in a radial array about the pilot sleeve portion141. The cross-holes 172A, 172B are fluidly coupled to an annular groove174 formed in an exterior peripheral surface of the pilot sleeve portion141. In the ventable valve mode of operation depicted in FIG. 1, becausethe pilot check ball 139 remain seated at the pilot seat 136, fluid isnot communicated to the cross-holes 172A, 172B or the annular groove174.

The valve 100 is further configured to operate in a second mode ofoperation, which can be referred to as a pressure relief mode, whenactuated. In other words, when the solenoid actuator 106 is activated,the valve 100 switches to a pressure relief mode of operation.

FIG. 3 illustrates a cross-sectional side view of the valve 100 in apressure relief mode of operation, in accordance with an exampleimplementation. When an electric current is provided through thewindings of the solenoid coil 151, a magnetic field is generated. Thepole piece 156 directs the magnetic field through the airgap 158 towardthe armature 152, which is movable and is attracted toward the polepiece 156. In other words, when an electric current is applied to thesolenoid coil 151, the generated magnetic field forms a north and southpole in the pole piece 156 and the armature 152, and therefore the polepiece 156 and the armature 152 are attracted to each other. Because thepole piece 156 is fixed and the armature 152 is movable, the armature152 can traverse the airgap 158 toward the pole piece 156, and theairgap 158 is reduced in size as depicted in FIG. 3. As such, a solenoidforce is applied on the armature 152, where the solenoid force is apulling force that tends to pull the armature 152 in the proximaldirection against the force of the solenoid spring 164.

The solenoid force applied to the armature 152 is also applied to thesolenoid actuator sleeve 154, which is coupled to the armature 152 asdescribed with respect to FIG. 2. As the solenoid actuator sleeve 154moves in the proximal direction (to the left in FIG. 3) to a secondposition shown in FIG. 3, the cross-holes 155A, 155B of the solenoidactuator sleeve 154 move away from the radial channel 134 of the pilotseat member 130.

As such, the first pilot flow path described above is blocked and nopilot flow is allowed from the first port 112 to the second port 114therethrough. In other words, as the solenoid actuator sleeve 154 movesin the proximal direction and the cross-holes 155A, 155B of the solenoidactuator sleeve 154 are no longer fluidly coupled to, or overlappingwith, the radial channel 134 as shown in FIG. 3, flow from the firstport 112 to the second port 114 through the orifice 128, the mainchamber 120, the longitudinal channel 132 and the radial channel 134 isblocked by the solenoid actuator sleeve 154. As a result, no pressuredrop occurs across the orifice 128, and the piston 118 becomespressure-balanced due to the pressure level of fluid at the first port112 and within the main chamber 120 being substantially the same. Thepiston 118 then moves back in the distal direction by the biasing forceof the main spring 122 to block the main flow cross-holes 115A, 115B andpreclude venting fluid from the first port 112 to the second port 114.

In the actuated position or state shown in FIG. 3, the valve 100operates in a pressure relief mode and can be used to control or limitpressure level in a hydraulic system. Particularly, in the actuatedstate when the solenoid actuator sleeve 154 is in the second position,the cross-holes 155A, 155B become aligned with, or partiallyoverlapping, the annular groove 174 and the cross-holes 172A, 172B,respectively. As such, the valve 100 is configured to open a secondpilot flow path from the first port 112 to the second port 114 whenpressure level of fluid at the first port 112, which is communicated tothe pilot check ball 139 and pilot poppet 138 via the orifice 128, themain chamber 120, and the longitudinal channel 132, reaches apredetermined setting pressure determined by the setting spring 144. Thepredetermined setting pressure is determined by dividing a preload forcethat the setting spring 144 applies to the pilot poppet 138 by theeffective area of the pilot seat 136 (e.g., the circular area having thediameter of the pilot seat 136, which can be slightly larger than thediameter of the longitudinal channel 132).

Once the pressure level in the main chamber 120 exceeds thepredetermined setting pressure, fluid in the main chamber 120 pushes thepilot check ball 139 and the pilot poppet 138 in the proximal direction(to the left in FIG. 3) off the pilot seat 136. As an example forillustration, the pilot check ball 139 and the pilot poppet 138 can movea distance of about 0.05 inches off the pilot seat 136.

As a result of the pilot check ball 139 and the pilot poppet 138 beingunseated, a second pilot flow path is formed and pilot flow is generatedfrom the first port 112 through the orifice 128, the main chamber 120,the longitudinal channel 132, to within the pilot sleeve portion 141(e.g., the pilot chamber 142) then through the cross-hole 172A, 172B,the annular groove 174, the cross-holes 155A, 155B, the annular space166, the longitudinal through-hole 168, the annular groove 170, and thepilot flow cross-hole 116 to the second port 114. As such, when thevalve 100 is actuated, the first pilot flow path that includes theradial channel 134 is blocked; however, when the pressure level exceedsthe pressure relief setting of the valve 100, a second pilot flow paththat includes the cross-holes 172A, 172B and the annular groove 174 isformed and allows pilot flow therethrough.

The pilot flow causes a pressure drop across the orifice 128, therebycausing the piston 118 to be subjected to a force imbalance and to movein the proximal direction against the main spring 122. Axial movement ofthe piston 118 past edges of the main flow cross-holes 115A, 115B allowsmain flow from the first port 112 through the main flow cross-holes115A, 115B to the second port 114. As such, pressurized fluid at thefirst port 112 is relieved to the second port 114, thereby precludingpressure level at the first port 112 from increasing further.

The valve 100 can be referred to as a fixed setting pressure reliefvalve because once the preload of the setting spring 144 is set by thelocation of the spring preload adjustment screw 148 and the solenoidactuator 106 is installed, the preload of the setting spring 144 and itsbiasing force cannot be changed without disassembling the valve 100. Insome applications, it may be desirable to have a manual adjustmentactuator coupled to the valve so as to allow for manual modification ofthe preload of the setting spring 144, and thus modification of thepressure relief setting on the valve, while the valve is installed inthe hydraulic system without disassembling the valve.

FIG. 4 illustrates a cross-section side view of a valve 400 having amanual adjustment actuator 402, in accordance with an exampleimplementation. Identical components of both valves 100, 400 aredesignated with the same reference numbers. The valve 400 includes asolenoid tube 404 that differs from the solenoid tube 150 in that thesolenoid tube 404 has a two-chamber configuration that allows it toreceive the manual adjustment actuator 402.

FIG. 5 illustrates a cross-sectional side view of the solenoid tube 404,in accordance with an example implementation. As depicted, the solenoidtube 404 has a cylindrical body 500 having therein a first chamber 502within a distal side of the cylindrical body 500 and a second chamber504 within a proximal side of the cylindrical body 500. The solenoidtube 404 includes a pole piece 503 formed as a protrusion from aninterior peripheral surface of the cylindrical body 500. The pole piece503 separates the first chamber 502 from the second chamber 504. Inother words, the pole piece 503 divides a hollow interior of thecylindrical body 500 into the first chamber 502 and the second chamber504. The pole piece 503 can be composed of material of high magneticpermeability.

Further, the pole piece 503 defines a channel 505 therethrough. In otherwords, an interior peripheral surface of the solenoid tube 404 at orthrough the pole piece 503 forms the channel 505, which fluidly couplesthe first chamber 502 to the second chamber 504. As such, pressurizedfluid provided to the first chamber 502 is communicated through thechannel 505 to the second chamber 504.

In examples, the channel 505 can be configured to receive a pintherethrough so as to transfer linear motion of one component in thesecond chamber 504 to another component in the first chamber 502 andvice versa. As such, the channel 505 can include chamferedcircumferential surfaces at its ends (e.g., an end leading into thefirst chamber 502 and another end leading into the second chamber 504)to facilitate insertion of such a pin therethrough.

The solenoid tube 404 has a distal end 506 configured to be coupled tothe housing 108 and a proximal end 508 configured to be coupled to andreceive the manual adjustment actuator 402. Particularly, the solenoidtube 404 can have a first threaded region 510 disposed on an exteriorperipheral surface of the cylindrical body 500 at the distal end 506that is configured to threadedly engage with corresponding threadsformed in the interior peripheral surface of the housing 108.

Also, the solenoid tube 404 can have a second threaded region 512disposed on the exterior peripheral surface of the cylindrical body 500at the proximal end 508 and configured to be threadedly engage withcorresponding threads formed in the interior peripheral surface of thecoil nut 153. Further, the solenoid tube 404 can have a third threadedregion 514 disposed on an interior peripheral surface of the cylindricalbody 500 at the proximal end 508 and configured to threadedly engagewith corresponding threads formed in a component of the manualadjustment actuator 402 as described below. The solenoid tube 404 canalso have one or more shoulders formed in the interior peripheralsurface of the cylindrical body 500 that can mate with respectiveshoulders of the manual adjustment actuator 402 to enable alignment ofthe manual adjustment actuator 402 within the solenoid tube 404.

Referring back to FIG. 4, the solenoid tube 404 is configured to housean armature 406 in the first chamber 502. The armature 406 has alongitudinal channel 408 formed therein. The armature 406 also includesan annular internal groove or T-slot 410 configured to receive the maleT-shaped member 200 of the solenoid actuator sleeve 154. The armature406 further includes a protrusion 412 from its interior peripheralsurface. The solenoid spring 164 is configured to rest on the protrusion412 to bias the armature 406 in the distal direction.

As mentioned above, the solenoid tube 404 includes the pole piece 503formed as a protrusion from the interior peripheral surface of thesolenoid tube 404. The pole piece 503 is separated from the armature 406by the airgap 158.

The manual adjustment actuator 402 is configured to allow for adjustingthe pressure relief setting of the valve 400 without disassembling thevalve 400. The manual adjustment actuator 402 includes a pin 414disposed through the channel 505. The pin 414 is coupled to a spring cap416 that interfaces with the setting spring 144 of the valve 400. Assuch, the valve 400 differs from the valve 100 in that, rather than thesetting spring 144 interfacing with the spring preload adjustment screw148, which is fixed once screwed to a particular position, the valve 400includes the spring cap 416, which is movable via the pin 414 and canadjust the length of the setting spring 144.

The manual adjustment actuator 402 includes an adjustment piston 418that interfaces with or contacts the pin 414, such that longitudinal oraxial motion of the adjustment piston 418 causes the pin 414 and thespring cap 416 coupled thereto to move axially therewith. The adjustmentpiston 418 can be threadedly coupled to a nut 420 at threaded region422. The nut 420 in turn is threadedly coupled to the solenoid tube 404at the threaded region 514. As such, the adjustment piston 418 iscoupled to the solenoid tube 404 via the nut 420. Further, theadjustment piston 418 is threadedly coupled at threaded region 424 toanother nut 426.

The adjustment piston 418 is axially movable within the second chamber504 of the solenoid tube 404. For instance, the adjustment piston 418can include an adjustment screw 428, such that if the adjustment screw428 is rotated in a first rotational direction (e.g., clockwise) theadjustment piston 418 moves in the distal direction (e.g., to the rightin FIG. 4) by engaging more threads of the threaded regions 422, 424. Ifthe adjustment screw 428 is rotated in a second rotational direction(e.g., counter-clockwise) the adjustment piston 418 is allowed to movein the proximal direction (e.g., to the left in FIG. 4) by disengagingsome threads of the threaded regions 422, 424.

While the distal end of the setting spring 144 is coupled to or restsagainst the pilot poppet 138, the proximal end of the setting spring 144rests against the spring cap 416, which is coupled to the adjustmentpiston 418 via the pin 414. As such, axial motion of the adjustmentpiston 418 results in a change in the length of the setting spring 144.As a result, the biasing force that the setting spring 144 exerts on thepilot poppet 138, and thus the pressure relief setting of the valve 400,is changed. As such, the pressure relief setting of the valve 400 can beadjusted via the manual adjustment actuator 402 without disassemblingthe valve 400. As an example for illustration, the adjustment piston 418can have a stroke of about 0.15 inches, which corresponds to a pressurerelief setting range between 0 psi and 5000 psi.

The valve 400 is depicted in FIG. 4 in the ventable operation mode(similar to the valve 100 in FIG. 1). Similar to the valve 100, thevalve 400 can be switched to the pressure relief mode by energizing thesolenoid coil 151 so as to move the armature 406 and the solenoidactuator sleeve 154 in the proximal direction (e.g., to the left in FIG.4).

As a result of the solenoid actuator sleeve 154 moving in the proximaldirection, the first pilot flow path through the radial channel 134 isblocked, whereas the annular groove 174 and the cross-holes 172A, 172Bof the pilot sleeve portion 141 are aligned or partially overlapped withthe cross-holes 155A, 155B of the solenoid actuator sleeve 154. Thevalve 400 is thus switched to the pressure relief mode and can operatesimilar to the valve 100 as described above with respect to FIG. 3.

Particularly, the second pilot flow path through the cross-holes 172A,172B and the annular groove 174 is formed when the pressure reliefsetting is reached at the first port 112 and the pilot check ball 139 isunseated off the pilot seat 136. As a result of forming or opening thesecond pilot flow path, pilot flow is allowed therethrough, causing thepiston 118 to move and relieving fluid from the first port 112 to thesecond port 114. Further, the pressure relief setting of the valve 400can be adjusted via the manual adjustment actuator 402 to change thepressure level of the fluid at the first port 112 that can overcome thebiasing force of the setting spring 144 and unseat the pilot check ball139 and allow pilot flow to flow from the first port 112 to the secondport 114.

The configurations and components shown in FIGS. 1-5 are examples forillustration, and different configurations and components could be used.For example, components can be integrated into a single component or acomponent can be divided into multiple components. As another example,different types of springs could be used, and other components could bereplaced by components that perform a similar functionality. Further,although the solenoid actuator 106 is shown and described as a pull-typesolenoid actuator, in other example implementations the valve 100, 400can be configured such that a push-type solenoid actuator can be used,where the armature 152, 406 can be pushed in the distal direction whenthe solenoid coil 151 is energized.

The valves 100, 400 can be referred to as ventable pressure reliefvalves. Particularly, the valve 100 or 400 can be included in hydraulicsystems so as to vent the first port 112 to the second port 114 when thevalve is unactuated, and switch to a pressure relief mode to buildpressure in the hydraulic system and protect the hydraulic systemagainst undesirable increases in pressure level when the valve isactuated.

FIG. 6 illustrates a hydraulic system 600 using the valve 400, inaccordance with an example implementation. The valve 400 is depictedsymbolically in FIG. 6.

The hydraulic system 600 includes a source 602 of fluid. The source 602of fluid can, for example, be a pump configured to provide fluid to thefirst port 112 of the valve 400. Such pump can be a fixed displacementpump, a variable displacement pump, or a load-sensing variabledisplacement pump, as examples. Additionally or alternatively, thesource 602 of fluid can be an accumulator or another component (e.g., avalve) of the hydraulic system 600, such that the source 602 is fluidlycoupled to the first port 112 of the valve 400.

As described above, when the valve 400 is unactuated, the first pilotflow path allows pilot flow therethrough and the piston 118 is shiftedas shown in FIG. 4 to allow fluid at the first port 112 to be vented tothe second port 114, which is coupled to a tank 604. Venting the firstport 112 to the second port 114 is symbolized by fluid path 606 asdepicted in FIG. 6.

The hydraulic system 600 can further include a controller 608. Thecontroller 608 can include one or more processors or microprocessors andmay include data storage (e.g., memory, transitory computer-readablemedium, non-transitory computer-readable medium, etc.). The data storagemay have stored thereon instructions that, when executed by the one ormore processors of the controller 608, cause the controller 608 toperform operations described herein. Signal lines to and from thecontroller 608 are depicted as dashed lines in FIG. 6. The controller608 can receive input or input information comprising sensor informationvia signals from various sensors or input devices in the hydraulicsystem 600, and in response provide electric signals to variouscomponents of the hydraulic system 600.

For instance, the controller 608 can receive a command or inputinformation to switch the valve 400 from operating in a ventableoperation mode to a pressure relief mode. The command or inputinformation can be provided to the controller 608 to start buildingpressure in the hydraulic system 600. For example, the controller 608can operate the valve 400 in the ventable operation mode to unload thesource 602 until a speed of the engine or motor driving the source 602reaches a particular value. Once the particular speed value is reached,the controller 608 can switch the valve 400 to the pressure relief mode.In another example, the controller 608 can be configured to operate thevalve 400 in the ventable operation mode when the temperature ofhydraulic oil exceeds a particular temperature threshold, and switch thevalve 400 to the pressure relief mode when the temperature is below theparticular temperature threshold. In other examples, the controller 608can be configured to operate the valve 400 in the ventable operationmode to operate the hydraulic system 600 in a safety mode, and thenswitch the valve 400 to the pressure relief mode when the hydraulicsystem 600 is ready to be operational.

Thus, in response to the command or input information requesting orindicating the mode switch, the controller 608 can send a command signalto the solenoid coil 151 of the solenoid actuator 106 of the valve 400to generate a solenoid force on the armature 406. When the solenoidforce overcomes the biasing force of the solenoid spring 164, thearmature 406 and the solenoid actuator sleeve 154 move in the proximaldirection as described above. As a result, the first pilot flow path isblocked due to blocking fluid communication from the radial channel 134to the cross-holes 155A, 155B, and the cross-holes 172A, 172B and theannular groove 174 are fluidly coupled to the cross-holes 155A, 155B,rendering the valve operating in the pressure relief mode.

In the pressure relief mode, pressure level of fluid provided by thesource 602 is allowed to build up or increase, thus providingpressurized fluid to other portions, components, equipment, or actuatorsof the hydraulic system 600. Such other portions, components, equipment,or actuators are represented in FIG. 6 by block 609. For example,assuming that the block 609 represents an actuator (e.g., a hydrauliccylinder or motor), pressure level of fluid provided by the source 602is allowed to increase, and thus pressurized fluid is provided to theactuator and enables the actuator to be operated (e.g., allows a pistonof the actuator to extend or retract).

If the pressure level of fluid supplied by the source 602 exceeds thepressure setting of the valve 400, such that pressurized fluid at thefirst port 112 overcomes the biasing force of the setting spring 144,pressurized fluid unseats the pilot check ball 139 and the second pilotflow path is opened. Opening the second pilot flow path allows pilotflow, symbolized by arrow 610 in FIG. 6, from the first port 112 to thesecond port 114 through the cross-holes 172A, 172B, the annular groove174, and the cross-holes 155A, 155B. The pilot flow allows the piston118 to move, thereby allowing main flow from the first port 112 to thesecond port 114 via the main flow cross-holes 115A, 115B and relievingfluid at the first port 112. The pressure relief mode is represented bysymbol 612 in FIG. 6.

As depicted symbolically in FIG. 6 by arrow 614, the biasing force ofthe setting spring 144 can be adjusted (e.g., via the manual adjustmentactuator 402 as described above). The valve 100 can be used in thehydraulic system 600 instead of the valve 400; however, the valve 100can be depicted without the arrow 614.

FIG. 7 is a flowchart of a method 700 for controlling a hydraulicsystem, in accordance with an example implementation. The method 700can, for example, be performed by a controller such as the controller608 to control the hydraulic system 600.

The method 700 may include one or more operations, or actions asillustrated by one or more of blocks 702-704. Although the blocks areillustrated in a sequential order, these blocks may in some instances beperformed in parallel, and/or in a different order than those describedherein. Also, the various blocks may be combined into fewer blocks,divided into additional blocks, and/or removed based upon the desiredimplementation.

In addition, for the method 700 and other processes and operationsdisclosed herein, the flowchart shows operation of one possibleimplementation of present examples. In this regard, each block mayrepresent a module, a segment, or a portion of program code, whichincludes one or more instructions executable by a processor or acontroller for implementing specific logical operations or steps in theprocess. The program code may be stored on any type of computer readablemedium or memory, for example, such as a storage device including a diskor hard drive. The computer readable medium may include a non-transitorycomputer readable medium or memory, for example, such ascomputer-readable media that stores data for short periods of time likeregister memory, processor cache and Random Access Memory (RAM). Thecomputer readable medium may also include non-transitory media ormemory, such as secondary or persistent long term storage, like readonly memory (ROM), optical or magnetic disks, compact-disc read onlymemory (CD-ROM), for example. The computer readable media may also beany other volatile or non-volatile storage systems. The computerreadable medium may be considered a computer readable storage medium, atangible storage device, or other article of manufacture, for example.In addition, for the method 700 and other processes and operationsdisclosed herein, one or more blocks in FIG. 7 may represent circuitryor digital logic that is arranged to perform the specific logicaloperations in the process.

At block 702, the method 700 includes receiving input informationindicating a request to switch the valve 100, 400 from operating in aventable mode to a pressure relief mode. The valve 100, 400 is normallyoperating in the ventable mode as described above with respect to FIGS.1 and 4 when the valve 100, 400 is unactuated.

At block 704, the method 700 includes, based on the input information,sending a signal to the solenoid coil 151 to switch the valve 100, 400to operate in the pressure relief mode. As described above, thecontroller 608 can provide a signal to the solenoid coil 151 to causethe armature 152, 406 to apply a force on the solenoid actuator sleeve154 in the proximal direction, such that as the solenoid actuator sleeve154 moves, the valve 100, 400 is switched to operating in the pressurerelief mode as described above.

FIG. 8 is a flowchart of a method 800 for operating a valve, inaccordance with an example implementation. The method 800 shown in FIG.8 presents an example of a method that could be used with the valves100, 400, shown throughout the Figures, for example. The method 800 mayinclude one or more operations, functions, or actions as illustrated byone or more of blocks 802-810. Although the blocks are illustrated in asequential order, these blocks may also be performed in parallel, and/orin a different order than those described herein. Also, the variousblocks may be combined into fewer blocks, divided into additionalblocks, and/or removed based upon the desired implementation. It shouldbe understood that for this and other processes and methods disclosedherein, flowcharts show functionality and operation of one possibleimplementation of present examples. Alternative implementations areincluded within the scope of the examples of the present disclosure inwhich functions may be executed out of order from that shown ordiscussed, including substantially concurrent or in reverse order,depending on the functionality involved, as would be understood by thosereasonably skilled in the art.

At block 802, the method 800 includes operating the valve 100, 400 in aventable mode where the first pilot flow path (e.g., through the radialchannel 134 and the cross-holes 155A, 155B) is opened to allow pilotflow from the first port 112 to the second port 114, thereby causing thepiston 118 to move (e.g., in the proximal direction) from a firstposition to a second position and allowing main flow from the first port112 to the second port 114. The first position of the piston 118 is aposition where the piston 118 can block the main flow cross-holes 115A,115B, and thus block main flow from the first port 112 to the secondport 114. The second position is a position where the piston 118 hasmoved to expose the main flow cross-holes 115A, 115B, and thus allowmain flow from the first port 112 to the second port 114 (as depicted inFIGS. 1 and 4).

At block 804, the method 800 includes receiving an electric signal(e.g., from the controller 608) energizing the solenoid coil 151 of asolenoid actuator (e.g., the solenoid actuator 106) of the valve 100,400. The controller 608 can receive a request to switch the valve 100,400 to a pressure relief mode. In response, the controller 608 sends theelectric signal to the solenoid coil 151 to energize it.

At block 806, the method 800 includes, responsively, causing thearmature 152, 406 of the solenoid actuator and the solenoid actuatorsleeve 154 coupled to the armature 152, 406 to move, thereby: (i)blocking the first pilot flow path, (ii) causing the piston 118 toreturn to the first position and block main flow from the first port 112to the second port 114, and (iii) aligning (or fluidly coupling) thecross-holes 155A, 155B of the solenoid actuator sleeve 154 with thecross-holes 172A, 172B of the pilot sleeve portion 141 of the valve 100,400.

At block 808, the method 800 includes receiving pressurized fluid havinga particular pressure level at the first port 112 of the valve 100, 400such that the pressurized fluid overcomes the biasing force of thesetting spring 144 of the valve 100, 400, thereby causing the pilotcheck member 140 (e.g., the pilot poppet 138 and the pilot check ball139) to be unseated and opening the second pilot flow path via thecross-holes 172A, 172B of the pilot sleeve portion 141 of the valve 100,400, which are aligned with the cross-holes 155A, 155B of the solenoidactuator sleeve 154.

At block 810, the method 800 includes, in response to pilot flow throughthe second pilot flow path, causing the piston 118 to move, therebyallowing main flow from the first port 112 to the second port 114.

The detailed description above describes various features and operationsof the disclosed systems with reference to the accompanying figures. Theillustrative implementations described herein are not meant to belimiting. Certain aspects of the disclosed systems can be arranged andcombined in a wide variety of different configurations, all of which arecontemplated herein.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall implementations, with the understanding that not allillustrated features are necessary for each implementation.

Additionally, any enumeration of elements, blocks, or steps in thisspecification or the claims is for purposes of clarity. Thus, suchenumeration should not be interpreted to require or imply that theseelements, blocks, or steps adhere to a particular arrangement or arecarried out in a particular order.

Further, devices or systems may be used or configured to performfunctions presented in the figures. In some instances, components of thedevices and/or systems may be configured to perform the functions suchthat the components are actually configured and structured (withhardware and/or software) to enable such performance. In other examples,components of the devices and/or systems may be arranged to be adaptedto, capable of, or suited for performing the functions, such as whenoperated in a specific manner.

By the term “substantially” or “about” it is meant that the recitedcharacteristic, parameter, or value need not be achieved exactly, butthat deviations or variations, including for example, tolerances,measurement error, measurement accuracy limitations and other factorsknown to skill in the art, may occur in amounts that do not preclude theeffect the characteristic was intended to provide.

The arrangements described herein are for purposes of example only. Assuch, those skilled in the art will appreciate that other arrangementsand other elements (e.g., machines, interfaces, operations, orders, andgroupings of operations, etc.) can be used instead, and some elementsmay be omitted altogether according to the desired results. Further,many of the elements that are described are functional entities that maybe implemented as discrete or distributed components or in conjunctionwith other components, in any suitable combination and location.

While various aspects and implementations have been disclosed herein,other aspects and implementations will be apparent to those skilled inthe art. The various aspects and implementations disclosed herein arefor purposes of illustration and are not intended to be limiting, withthe true scope being indicated by the following claims, along with thefull scope of equivalents to which such claims are entitled. Also, theterminology used herein is for the purpose of describing particularimplementations only, and is not intended to be limiting.

What is claimed is:
 1. A valve comprising: a pilot seat member comprising: (i) one or more channels fluidly coupled to a first port of the valve, (ii) a pilot seat, and (iii) a pilot sleeve portion comprising a pilot chamber and a cross-hole disposed in an exterior peripheral surface of the pilot sleeve portion; a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring disposed in the pilot chamber to seat the pilot check member at the pilot seat; and a solenoid actuator sleeve slidably accommodated about the exterior peripheral surface of the pilot sleeve portion of the pilot seat member, wherein the solenoid actuator sleeve includes a cross-hole disposed in an exterior peripheral surface of the solenoid actuator sleeve, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to a second port of the valve, and wherein: when the valve is unactuated, the cross-hole of the solenoid actuator sleeve is fluidly coupled to the one or more channels of the pilot seat member to form a first pilot flow path from the first port to the second port, thereby causing a piston to move and open a main flow path from the first port to the second port, and when the valve is actuated, the solenoid actuator sleeve moves axially, thereby: (i) blocking the first pilot flow path, (ii) causing the piston to block the main flow path from the first port to the second port, and (iii) aligning the cross-hole of the solenoid actuator sleeve with the cross-hole of the pilot sleeve portion, such that when pressure level of fluid at the first port overcomes the biasing force of the setting spring on the pilot check member, the pilot check member is unseated and a second pilot flow path is formed from the first port to the second port, thereby causing the piston to move axially and open the main flow path from the first port to the second port.
 2. The valve of claim 1, further comprising: a housing having a longitudinal cylindrical cavity therein and having a cross-hole disposed in an exterior peripheral surface of the housing; and a main sleeve disposed, at least partially, in the longitudinal cylindrical cavity of the housing, wherein the main sleeve includes the first port at a distal end of the main sleeve and includes one or more cross-holes disposed on an exterior peripheral surface of the main sleeve, wherein the cross-hole of the housing and the one or more cross-holes of the main sleeve form the second port.
 3. The valve of claim 2, wherein the piston is disposed within the main sleeve and configured to be axially movable therein, wherein the piston defines a main chamber therein, and wherein the main chamber is fluidly coupled to the first port and the one or more channels of the pilot seat member.
 4. The valve of claim 3, wherein the one or more channels of the pilot seat member comprise: (i) a longitudinal channel fluidly coupled to the main chamber, wherein the pilot seat is formed at a proximal end of the longitudinal channel, and (ii) a radial channel fluidly coupled to the longitudinal channel, and wherein the first pilot flow path comprises the longitudinal channel, the radial channel, and the cross-hole of the solenoid actuator sleeve.
 5. The valve of claim 4, wherein the second pilot flow path comprises: the longitudinal channel, the cross-hole of the pilot sleeve portion, and the cross-hole of the solenoid actuator sleeve, which is aligned with the cross-hole of the pilot sleeve portion when the valve is actuated.
 6. The valve of claim 5, wherein the first pilot flow path and the second pilot flow path further comprise: (i) an annular space formed between an exterior peripheral surface of the solenoid actuator sleeve and an interior peripheral surface of the housing, (ii) a longitudinal through-hole formed in the pilot seat member, and (iii) the cross-hole of the housing.
 7. The valve of claim 1, further comprising: a solenoid actuator comprising a solenoid coil, a pole piece, and an armature that is mechanically coupled to the solenoid actuator sleeve, such that when the solenoid coil is energized, the armature and the solenoid actuator sleeve coupled thereto are pulled axially toward the pole piece, thereby aligning the cross-hole of the solenoid actuator sleeve with the cross-hole of the pilot sleeve portion.
 8. The valve of claim 7, wherein the armature comprises a T-slot formed as an annular internal groove, wherein the solenoid actuator sleeve comprises a male T-shaped member, and wherein the T-slot of the armature is configured to receive the male T-shaped member of the solenoid actuator sleeve to mechanically couple the armature to the solenoid actuator sleeve.
 9. The valve of claim 7, wherein the solenoid actuator further comprises a solenoid tube, and wherein the solenoid tube comprises: (i) a cylindrical body, (ii) a first chamber defined within the cylindrical body and configured to receive the armature of the solenoid actuator therein, and (iii) a second chamber defined within the cylindrical body, wherein the pole piece is formed as a protrusion from an interior peripheral surface of the cylindrical body, wherein the pole piece is disposed between the first chamber and the second chamber, and wherein the pole piece defines a channel therethrough, such that the channel fluidly couples the first chamber to the second chamber.
 10. The valve of claim 9, further comprising: a manual adjustment actuator having: (i) an adjustment piston disposed, at least partially, in the second chamber of the solenoid tube, (ii) a pin disposed through the channel of the pole piece and through the armature, wherein a proximal end of the pin contacts the adjustment piston and a distal end of the pin is coupled to a spring cap against which a proximal end of the setting spring rests, such that axial motion of the adjustment piston causes the pin and the spring cap coupled thereto to move axially, thereby adjusting the biasing force of the setting spring.
 11. A hydraulic system comprising: a source of fluid; a reservoir; and a ventable pressure relief valve having a first port fluidly coupled to the source of fluid, and a second port fluidly coupled to the reservoir, wherein the ventable pressure relief valve comprises: a pilot seat member comprising: (i) one or more channels fluidly coupled to the first port, (ii) a pilot seat, and (iii) a pilot sleeve portion comprising a pilot chamber and a cross-hole disposed in an exterior peripheral surface of the pilot sleeve portion, a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring disposed in the pilot chamber to seat the pilot check member at the pilot seat, and a solenoid actuator sleeve slidably accommodated about the exterior peripheral surface of the pilot sleeve portion of the pilot seat member, wherein the solenoid actuator sleeve includes a cross-hole disposed in an exterior peripheral surface of the solenoid actuator sleeve, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to the second port, and wherein: when the ventable pressure relief valve is unactuated, the ventable pressure relief valve operates in a ventable mode of operation, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to the one or more channels of the pilot seat member to form a first pilot flow path from the first port to the second port, thereby causing a piston to move and open a main flow path from the first port to the second port, and when the ventable pressure relief valve is actuated, the ventable pressure relief valve operates in a pressure relief mode of operation, wherein the solenoid actuator sleeve moves axially, thereby: (i) blocking the first pilot flow path, (ii) causing the piston to block the main flow path from the first port to the second port, and (iii) aligning the cross-hole of the solenoid actuator sleeve with the cross-hole of the pilot sleeve portion, such that when pressure level of fluid at the first port overcomes the biasing force of the setting spring on the pilot check member, the pilot check member is unseated and a second pilot flow path is formed from the first port to the second port, thereby causing the piston to move axially and open the main flow path from the first port to the second port.
 12. The hydraulic system of claim 11, wherein the ventable pressure relief valve further comprises: a housing having a longitudinal cylindrical cavity therein and having a cross-hole disposed in an exterior peripheral surface of the housing; and a main sleeve disposed, at least partially, in the longitudinal cylindrical cavity of the housing, wherein the main sleeve includes the first port at a distal end of the main sleeve and includes one or more cross-holes disposed on an exterior peripheral surface of the main sleeve, wherein the cross-hole of the housing and the one or more cross-holes of the main sleeve form the second port, wherein the piston is disposed within the main sleeve and configured to be axially movable therein, wherein the piston defines a main chamber therein, and wherein the main chamber is fluidly coupled to the first port and the one or more channels of the pilot seat member.
 13. The hydraulic system of claim 12, wherein the one or more channels of the pilot seat member comprise: (i) a longitudinal channel fluidly coupled to the main chamber, wherein the pilot seat is formed at a proximal end of the longitudinal channel, and (ii) a radial channel fluidly coupled to the longitudinal channel, and wherein the first pilot flow path comprises the longitudinal channel, the radial channel, and the cross-hole of the solenoid actuator sleeve, wherein the second pilot flow path comprises: the longitudinal channel, the cross-hole of the pilot sleeve portion, and the cross-hole of the solenoid actuator sleeve, which is aligned with the cross-hole of the pilot sleeve portion when the ventable pressure relief valve is actuated.
 14. The hydraulic system of claim 13, wherein the first pilot flow path and the second pilot flow path further comprise: (i) an annular space formed between an exterior peripheral surface of the solenoid actuator sleeve and an interior peripheral surface of the housing, (ii) a longitudinal through-hole formed in the pilot seat member, and (iii) the cross-hole of the housing.
 15. The hydraulic system of claim 11, further comprising: a solenoid actuator comprising a solenoid coil, a pole piece, and an armature that is mechanically coupled to the solenoid actuator sleeve, such that when the solenoid coil is energized, the armature and the solenoid actuator sleeve coupled thereto are pulled axially toward the pole piece, thereby aligning the cross-hole of the solenoid actuator sleeve with the cross-hole of the pilot sleeve portion.
 16. The hydraulic system of claim 15, wherein the solenoid actuator further comprises a solenoid tube, and wherein the solenoid tube comprises: (i) a cylindrical body, (ii) a first chamber defined within the cylindrical body and configured to receive the armature of the solenoid actuator therein, and (iii) a second chamber defined within the cylindrical body, wherein the pole piece is formed as a protrusion from an interior peripheral surface of the cylindrical body, wherein the pole piece is disposed between the first chamber and the second chamber, and wherein the pole piece defines a channel therethrough, such that the channel fluidly couples the first chamber to the second chamber.
 17. The hydraulic system of claim 16, further comprising: a manual adjustment actuator having: (i) an adjustment piston disposed, at least partially, in the second chamber of the solenoid tube, (ii) a pin disposed through the channel of the pole piece and through the armature, wherein a proximal end of the pin contacts the adjustment piston and a distal end of the pin is coupled to a spring cap against which a proximal end of the setting spring rests, such that axial motion of the adjustment piston causes the pin and the spring cap coupled thereto to move axially, thereby adjusting the biasing force of the setting spring.
 18. A valve comprising: a housing having a longitudinal cylindrical cavity therein and having a cross-hole disposed in an exterior peripheral surface of the housing; a main sleeve disposed, at least partially, in the longitudinal cylindrical cavity of the housing, wherein the main sleeve includes a first port at a distal end of the main sleeve and includes one or more cross-holes disposed on an exterior peripheral surface of the main sleeve, wherein the cross-hole of the housing and the one or more cross-holes of the main sleeve form a second port; a piston disposed within the main sleeve and configured to be axially movable therein, wherein the piston defines a main chamber therein, and wherein the main chamber is fluidly coupled to the first port via an orifice; a pilot seat member comprising: (i) one or more channels fluidly coupled to the main chamber, (ii) a pilot seat, and (iii) a pilot sleeve portion comprising a pilot chamber and a cross-hole disposed in an exterior peripheral surface of the pilot sleeve portion; a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring disposed in the pilot chamber to seat the pilot check member at the pilot seat; and a solenoid actuator sleeve slidably accommodated about the exterior peripheral surface of the pilot sleeve portion of the pilot seat member, wherein the solenoid actuator sleeve includes a cross-hole disposed in an exterior peripheral surface of the solenoid actuator sleeve, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to the second port, wherein when the valve is unactuated, the solenoid actuator sleeve is in a first position in which the cross-hole of the solenoid actuator sleeve is fluidly coupled to the one or more channels of the pilot seat member to form a first pilot flow path from the first port to the second port, and wherein when the valve is actuated, the solenoid actuator sleeve moves axially to a second position in which the first pilot flow path is blocked, and the cross-hole of the solenoid actuator sleeve is aligned with the cross-hole of the pilot sleeve portion to form a second pilot flow path when pressure level of fluid at the first port overcomes the biasing force of the setting spring on the pilot check member.
 19. The valve of claim 18, wherein the one or more channels of the pilot seat member comprise: (i) a longitudinal channel fluidly coupled to the main chamber, wherein the pilot seat is formed at a proximal end of the longitudinal channel, and (ii) a radial channel fluidly coupled to the longitudinal channel, and when the solenoid actuator sleeve is in the first position, the cross-hole of the solenoid actuator sleeve is aligned with the radial channel, and the first pilot flow path comprises the longitudinal channel, the radial channel, and the cross-hole of the solenoid actuator sleeve.
 20. The valve of claim 19, wherein when the solenoid actuator sleeve is in the second position, the radial channel is blocked, and wherein the second pilot flow path comprises: the longitudinal channel, the cross-hole of the pilot sleeve portion, and the cross-hole of the solenoid actuator sleeve, which is aligned with the cross-hole of the pilot sleeve portion when the solenoid actuator sleeve is in the second position. 